The Liquid Crystal Display (LCD) is one of the most widely utilized flat panel displays, and the liquid crystal display panel is the core component of the Liquid Crystal Display. The liquid crystal panel generally comprises a Color Filter Substrate (CF Substrate), a Thin Film Transistor Array Substrate (TFT Array Substrate) and a Liquid Crystal Layer arranged between the two substrates. Generally, the pixel electrode and the common electrode are respectively arranged on the array substrate and the color filter substrate. As the voltages are applied to the pixel electrodes and the common electrodes, the electrical field can be generated in the liquid crystal layer, and the electrical field determines the orientation of the liquid crystal molecules, and then to adjust the polarization of the light incident into the liquid crystal layer for making the liquid crystal display panel show images.
As a leader in a flat panel display, the liquid crystal display possesses properties of low power consumption, excellent display quality and higher production yield, and now has been gradually dominates the flat panel display field. In the liquid crystal display, the classifications of the liquid crystal display modes based on the liquid crystal operation mode mainly comprise: phase change (PC), twisted nematic (TN), super twisted nematic (STN), Vertical Alignment (VA), In plane Switching (IPS) and fringe field switching (FFS). In these various display technologies, the alignments are different. At present, in the production of the liquid crystal display panel, the alignment skill which is widely used is Rubbing alignment. The Rubbing alignment is to use fabric roller to perform contacting directional mechanical friction on the macromolecular surface. The energy provided by rubbing the macromolecular surface make the macromolecular main chain be aligned in direction due to the extension, and thus the liquid crystal orientation and alignment are controlled. The Rubbing alignment can provide stronger alignment ability for the liquid crystal molecules. However, in the rubbing process, the pollutions of the electrostatic and particles will generate due to the contacting friction of the fabric, and these pollutions often cause the damage of the liquid crystal element. Therefore, either in the academia or in the industry, the non contact alignment has been continuously researched and improved. Not only the pollutions of the electrostatic and particles can be prevented, the alignment of the liquid crystal molecules can be controlled more easily. With the non contact alignment, the small area alignment can be implemented with the mask having some particular pattern for manufacturing the liquid crystal element of special needs. The well known non contact alignment is irradiate the alignment agent having photosensitizer with the linearly polarized UV light, which is so called the UV light alignment, and also named as the photo alignment.
The photo alignment is to use the linearly polarized UV light to irradiate on the polymer alignment film having photosensitizer to make the polymer possess the alignment ability. The merit is that the pollution to the surface of the glass substrate can be prevented, and the small area alignment can be conducted, and the pattern alignment can be done with the mask, and with utilizing the angle of the incident light and the duration of the irradiation time, the parameters of the liquid crystal unit, such as the pre-tilted angle, the surface orientation strength can be controlled. The photo alignment agent is a kind of Polymer, which is consisted of many monomer small molecule bonds. By baking or irradiating thereto, the monomers are bonded with one another to form the macromolecules. In the liquid crystal alignment, for aligning the liquid crystal molecules along the alignment direction of the alignment molecules, the long chain molecules are formed after the selected monomers are bonded.
The photo alignment skill can achieve that all the liquid crystal molecules are in the state of overall tilting along the designed direction with the alignment film. The liquid crystal molecules can tilt toward one direction at the same time after applying the electrical field, and the response speed is raised. Because a plurality of regions can be divided without the protrusions and the slits. The aperture ratio is raised in comparison with the panel in which the protrusions are used for dividing the plurality of regions, and the light leakage due to the scattering of the protrusion and slit parts can be prevented to raise the contrast of the liquid crystal display panel. However, as considering the view angle property and the color deviation under circumstance of the tilt angle, the panel has to be partitioned so that the liquid crystal tilts in one sub pixel can have many directions for compensating the tilt angle properties and the color deviation. As utilizing the mask for partitioning the panel, the movement of the mask will result in the alignment precision loss and influence the panel quality.